font/sfnt: flip the Y axis for LoadGlyph's Segments.

The underlying font format's Y axis increases up. The Go standard
graphics libraries' Y axis increases down. This change makes the Go API
consistent with the other Go libraries.

Also change Segment.Args from [6]fixed.Int26_6 to [3]fixed.Point26_6 to
emphasize that the Args are consistent with other fixed.Point26_6 use.

Change-Id: Idd7b89eb4d86890dea477ac2ef96ff8f6b1dee8d
Reviewed-by: David Crawshaw <>
5 files changed